/*-
 * Copyright (c) 2009 Jonathan Anderson
 * All rights reserved.
 *
 * WARNING: THIS IS EXPERIMENTAL SECURITY SOFTWARE THAT MUST NOT BE RELIED
 * ON IN PRODUCTION SYSTEMS.  IT WILL BREAK YOUR SOFTWARE IN NEW AND
 * UNEXPECTED WAYS.
 * 
 * This software was developed at the University of Cambridge Computer
 * Laboratory with support from a grant from Google, Inc. 
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef CACHE_H

#include <openssl/aes.h>

#include <QString>
#include <map>

#include "File.h"


/**
 * The file cache works like a coat check: you give it something valuable and it
 * gives you a token which can be used to retrieve it later. You can choose to
 * only store the descriptor until you retrieve it, or you can leave it cached
 * for later use if you prefer.
 */
class Cache
{
	public:
	//! Singleton accessor
	static Cache& instance();


	/**
	 * Store a file descriptor.
	 *
	 * @param   fd            the file descriptor to store
	 * @param   persistent    the descriptor will be stored until the client
	 *                        which stored it disconnects
	 */
	void store(File, bool persistent);


	/**
	 * Retrieve a file descriptor from the cache.
	 *
	 * @param   token         the crypto token which names the descriptor
	 *
	 * @return  the file descriptor
	 */
	File retrieve(QString token);


	protected:
	Cache();


	private:
	AES_KEY encryptKey, decryptKey, macKey;

	struct FileEntry;
	std::map<QString,FileEntry> files;
};


#define CACHE_H
#endif

